   "returns a reagent/reaction which observes a part of the "
   [v]
   (let [key-v       (first-in-vector v)
-       handler-fn  (get @key->fn key-v)]
+        handler-fn  (get @key->fn key-v)]
     (if (nil? handler-fn)
-      (warn "re-frame: no subscription handler registered for: \"" key-v "\".  Returning nil.")
+      (warn "re-frame: no subscription handler registered for: \"" key-v "\".  Returning a nil subscription.")
       (handler-fn app-db v))))

(ns re-frame.subs
 (:require
  [re-frame.db :refer [app-db]]
  [re-frame.utils :refer [first-in-vector warn]]))



  "register a hander function for an id"
  [key-v handler-fn]
  (if (contains? @key->fn key-v)
    (warn "re-frame: overwriting subscription-handler for: " key-v))   ;; allow it, but warn.
  (swap! key->fn assoc key-v handler-fn))


